Cylinder liner and method of forming the same

Abstract

A high strength cast iron material for application in heavy duty diesel engines with Pa peak cylinder pressure greater than 240 bar is disclosed, the material a ductile material austempered to get a ausferrite matrix structure with higher mechanical properties than conventional cast iron materials available by using a designed low cost alloying cast material with heat treatment. Furthermore, the cylinder liner may be formed using novel heat treatment and/or fine honing processes to improve the properties thereof.

I claim: 
     
       1. A cylinder liner comprising:
 an inner sidewall formed from a microstructure comprising ausferrite, nodular graphite, between about 3.55 wt % and about 3.65 wt % C, and between about 0.005% and about 0.06% Mg, wherein the microstructure includes graphite-nodular (form I) >80%, nodule size class 6-7 (20-30 μm), and matrix-acicular ausferrite. 
 
     
     
       2. The cylinder liner of  claim 1 , wherein the ausferrite of the sidewall is formed from a combination of high carbon enriched metastable austenite plus acicular ferrite. 
     
     
       3. The cylinder liner of  claim 1 , wherein the sidewall is substantially free from flake graphite. 
     
     
       4. The cylinder liner of  claim 1 , wherein the sidewall includes between about 2.30 wt % and about 2.40 wt % Si. 
     
     
       5. The cylinder liner of  claim 4 , wherein the sidewall includes between about 0.45 wt % and about 0.50 wt % Mn. 
     
     
       6. The cylinder liner of  claim 5 , wherein the sidewall includes between about 0.020 wt % and about 0.030 wt % P. 
     
     
       7. The cylinder liner of  claim 6 , wherein the sidewall includes between about 0.15 wt % and about 0.25 wt % S. 
     
     
       8. The cylinder liner of  claim 7 , wherein the sidewall includes between about 0.80 wt % and about 0.90 wt % Cu. 
     
     
       9. The cylinder liner of  claim 8 , wherein the sidewall includes between about 0.30 wt % and about 0.40 wt % Ni. 
     
     
       10. The cylinder liner of  claim 9 , wherein the sidewall includes between about 0.10 qt % and about 0.20 wt % Mo. 
     
     
       11. The cylinder liner of  claim 10 , wherein the sidewall includes between about 0.005 wt % and about 0.06 wt %. 
     
     
       12. The cylinder liner of  claim 11 , wherein the sidewall is substantially free from Cr. 
     
     
       13. The cylinder liner of  claim 12 , wherein the sidewall includes about 3.62 wt % C, about 2.36 wt % Si, about 0.49 wt % Mn, about 0.27 wt % P, about 0.20 wt % S, about 0.87 wt % Cu, about 0.34 wt % Ni, and about 0.14 wt % Mo. 
     
     
       14. A cylinder liner comprising:
 a sidewall formed from a microstructure comprising ausferrite and nodular graphite, wherein the microstructure includes graphite-nodular (form I) >80%, nodule size class 6-7 (20-30 μm), and matrix-acicular ausferrite, the sidewall consisting essentially of:
 between about 3.55 wt % and about 3.65 wt % C, 
 between about 2.30 wt % and about 2.40 wt % Si, 
 between about 0.45 wt % and about 0.50 wt % Mn, 
 between about 0.020 wt % and about 0.030 wt % P, 
 between about 0.15 wt % and about 0.25 wt % S, 
 between about 0.80 wt % and about 0.90 wt % Cu, 
 between about 0.30 wt % and about 0.40 wt % Ni, 
 between about 0.10 wt % and about 0.20 wt % Mo, and 
 between about 0.005% and about 0.06% Mg.